LIANG Dong, LIU Wei, YANG Zhong-tian, GUO Xi-liang, YANG Wei-bing, LI Hong-hui, ZHAO Shuai-wei

(CNNC Key Laboratory on Geological Disposal of High-level Radioactive Waste, China Institute for Radiation Protection, Taiyuan 030006, China)

Abstract：The aim of this paper is to demonstrate the impacts of gamma radiation on modified sodium bentonite and to broaden the assessment and scope of buffer materials for geological disposal of high-level radioactive waste (HLW) in line with the rapid advancement of HLW repository research. Characteristics and analyses are made of the properties and microstructure of modified sodium bentonite from Gaomiaozi area, Inner Mongolia, China under accumulative radiation with doses at 1000 kGy, 2000 kGy, 3000 kGy, 4000 kGy and 5000 kGy, respectively. The analyses were done using DSC, FTIR and a X-ray diffractometer. Results indicate that, even being radiated at the high dose of 5000 kGy, with increasing thermal resistance performance, only minimal chemical changes were observed in some functional groups of Gaomiaozi modified sodium bentonite. As well, less impacts on interlayer water and absorbed moisture can be found. Furthermore, there is no significant changes in microstructure, but only some decrease in the size of crystal cell was detected. In general, the Gaomiaozi modified sodium bentonite has good stability in its microstructure under high dose exposure to Gamma radiation .

Keywords: modified sodium bentonite; buffer material; high-level radioactive waste; geological disposal; gamma radiation exposure; stability

E-mail: londonliang@yeah.net

ACTA MINERALOGICA SINICA Vol. 35, No. 1, 2015, Page 103-106